1 /* 2 * max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs 3 * 4 * Based on arch/arm/mach-pxa/corgi_ssp.c 5 * 6 * Copyright (C) 2004-2005 Richard Purdie 7 * 8 * Copyright (C) 2008 Marvell International Ltd. 9 * Eric Miao <eric.miao@marvell.com> 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License version 2 as 13 * publishhed by the Free Software Foundation. 14 */ 15 16 #include <linux/module.h> 17 #include <linux/kernel.h> 18 #include <linux/init.h> 19 #include <linux/err.h> 20 #include <linux/hwmon.h> 21 #include <linux/hwmon-sysfs.h> 22 #include <linux/spi/spi.h> 23 #include <linux/slab.h> 24 25 #define MAX1111_TX_BUF_SIZE 1 26 #define MAX1111_RX_BUF_SIZE 2 27 28 /* MAX1111 Commands */ 29 #define MAX1111_CTRL_PD0 (1u << 0) 30 #define MAX1111_CTRL_PD1 (1u << 1) 31 #define MAX1111_CTRL_SGL (1u << 2) 32 #define MAX1111_CTRL_UNI (1u << 3) 33 #define MAX1111_CTRL_SEL_SH (5) /* NOTE: bit 4 is ignored */ 34 #define MAX1111_CTRL_STR (1u << 7) 35 36 struct max1111_data { 37 struct spi_device *spi; 38 struct device *hwmon_dev; 39 struct spi_message msg; 40 struct spi_transfer xfer[2]; 41 uint8_t *tx_buf; 42 uint8_t *rx_buf; 43 }; 44 45 static int max1111_read(struct device *dev, int channel) 46 { 47 struct max1111_data *data = dev_get_drvdata(dev); 48 uint8_t v1, v2; 49 int err; 50 51 data->tx_buf[0] = (channel << MAX1111_CTRL_SEL_SH) | 52 MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 | 53 MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR; 54 55 err = spi_sync(data->spi, &data->msg); 56 if (err < 0) { 57 dev_err(dev, "spi_sync failed with %d\n", err); 58 return err; 59 } 60 61 v1 = data->rx_buf[0]; 62 v2 = data->rx_buf[1]; 63 64 if ((v1 & 0xc0) || (v2 & 0x3f)) 65 return -EINVAL; 66 67 return (v1 << 2) | (v2 >> 6); 68 } 69 70 #ifdef CONFIG_SHARPSL_PM 71 static struct max1111_data *the_max1111; 72 73 int max1111_read_channel(int channel) 74 { 75 return max1111_read(&the_max1111->spi->dev, channel); 76 } 77 EXPORT_SYMBOL(max1111_read_channel); 78 #endif 79 80 /* 81 * NOTE: SPI devices do not have a default 'name' attribute, which is 82 * likely to be used by hwmon applications to distinguish between 83 * different devices, explicitly add a name attribute here. 84 */ 85 static ssize_t show_name(struct device *dev, 86 struct device_attribute *attr, char *buf) 87 { 88 return sprintf(buf, "max1111\n"); 89 } 90 91 static ssize_t show_adc(struct device *dev, 92 struct device_attribute *attr, char *buf) 93 { 94 int channel = to_sensor_dev_attr(attr)->index; 95 int ret; 96 97 ret = max1111_read(dev, channel); 98 if (ret < 0) 99 return ret; 100 101 return sprintf(buf, "%d\n", ret); 102 } 103 104 #define MAX1111_ADC_ATTR(_id) \ 105 SENSOR_DEVICE_ATTR(adc##_id##_in, S_IRUGO, show_adc, NULL, _id) 106 107 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); 108 static MAX1111_ADC_ATTR(0); 109 static MAX1111_ADC_ATTR(1); 110 static MAX1111_ADC_ATTR(2); 111 static MAX1111_ADC_ATTR(3); 112 113 static struct attribute *max1111_attributes[] = { 114 &dev_attr_name.attr, 115 &sensor_dev_attr_adc0_in.dev_attr.attr, 116 &sensor_dev_attr_adc1_in.dev_attr.attr, 117 &sensor_dev_attr_adc2_in.dev_attr.attr, 118 &sensor_dev_attr_adc3_in.dev_attr.attr, 119 NULL, 120 }; 121 122 static const struct attribute_group max1111_attr_group = { 123 .attrs = max1111_attributes, 124 }; 125 126 static int setup_transfer(struct max1111_data *data) 127 { 128 struct spi_message *m; 129 struct spi_transfer *x; 130 131 data->tx_buf = kmalloc(MAX1111_TX_BUF_SIZE, GFP_KERNEL); 132 if (!data->tx_buf) 133 return -ENOMEM; 134 135 data->rx_buf = kmalloc(MAX1111_RX_BUF_SIZE, GFP_KERNEL); 136 if (!data->rx_buf) { 137 kfree(data->tx_buf); 138 return -ENOMEM; 139 } 140 141 m = &data->msg; 142 x = &data->xfer[0]; 143 144 spi_message_init(m); 145 146 x->tx_buf = &data->tx_buf[0]; 147 x->len = 1; 148 spi_message_add_tail(x, m); 149 150 x++; 151 x->rx_buf = &data->rx_buf[0]; 152 x->len = 2; 153 spi_message_add_tail(x, m); 154 155 return 0; 156 } 157 158 static int __devinit max1111_probe(struct spi_device *spi) 159 { 160 struct max1111_data *data; 161 int err; 162 163 spi->bits_per_word = 8; 164 spi->mode = SPI_MODE_0; 165 err = spi_setup(spi); 166 if (err < 0) 167 return err; 168 169 data = kzalloc(sizeof(struct max1111_data), GFP_KERNEL); 170 if (data == NULL) { 171 dev_err(&spi->dev, "failed to allocate memory\n"); 172 return -ENOMEM; 173 } 174 175 err = setup_transfer(data); 176 if (err) 177 goto err_free_data; 178 179 data->spi = spi; 180 spi_set_drvdata(spi, data); 181 182 err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group); 183 if (err) { 184 dev_err(&spi->dev, "failed to create attribute group\n"); 185 goto err_free_all; 186 } 187 188 data->hwmon_dev = hwmon_device_register(&spi->dev); 189 if (IS_ERR(data->hwmon_dev)) { 190 dev_err(&spi->dev, "failed to create hwmon device\n"); 191 err = PTR_ERR(data->hwmon_dev); 192 goto err_remove; 193 } 194 195 #ifdef CONFIG_SHARPSL_PM 196 the_max1111 = data; 197 #endif 198 return 0; 199 200 err_remove: 201 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); 202 err_free_all: 203 kfree(data->rx_buf); 204 kfree(data->tx_buf); 205 err_free_data: 206 kfree(data); 207 return err; 208 } 209 210 static int __devexit max1111_remove(struct spi_device *spi) 211 { 212 struct max1111_data *data = spi_get_drvdata(spi); 213 214 hwmon_device_unregister(data->hwmon_dev); 215 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); 216 kfree(data->rx_buf); 217 kfree(data->tx_buf); 218 kfree(data); 219 return 0; 220 } 221 222 static struct spi_driver max1111_driver = { 223 .driver = { 224 .name = "max1111", 225 .owner = THIS_MODULE, 226 }, 227 .probe = max1111_probe, 228 .remove = __devexit_p(max1111_remove), 229 }; 230 231 static int __init max1111_init(void) 232 { 233 return spi_register_driver(&max1111_driver); 234 } 235 module_init(max1111_init); 236 237 static void __exit max1111_exit(void) 238 { 239 spi_unregister_driver(&max1111_driver); 240 } 241 module_exit(max1111_exit); 242 243 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>"); 244 MODULE_DESCRIPTION("MAX1111 ADC Driver"); 245 MODULE_LICENSE("GPL"); 246 MODULE_ALIAS("spi:max1111"); 247